1. Field of the Invention
The present invention relates to an elastomeric, strand-shaped sealing profile for a tunnel segment having a receiving groove, the strand profile including a base surface, a rear side surface having a width smaller than a width of the base surface, and two opposite lateral side surfaces connecting the base surface with the rear side surface, with the base, rear side, and lateral side surfaces defining together a base body.
2. Description of the Prior Art
Sealing profiles for sealing gaps between tunnel segments are disclosed, e.g., in DE-35 26 063A1, DE-37 20 919 A1, DE-40 26 076 A1, DE-41 03 089 A1, DE-196 03 188 A1, CH-679 510 A5, EP-306 581 A1, and EP-522,912 A1. For sealing of the tunnel segments with circumferential receiving grooves, usually, four sealing profiles are secured in an associated sealing frame provided in the circumferential receiving groove in associated frame corners. The tunnel segments or tubings with sealing profiles arranged in their receiving grooves, are assembled to form a ring, with the separate rings forming together a complete tunnel tube described, e.g., in DE-196 03 188A1. The sealing profiles, which are located in opposite, facing each other, receiving grooves of two tunnel segments, have their rear surfaces lying on each other and are, and the profiles become compressed to a greater and lesser degree. The stresses are generated by corresponding elastic restoring forces, whereby the tunnel segments become sealed. Thereby, a long-lasting sealing against an increased water pressure in the soil or resulting from chasms is achieved.
As a rule, the water pressure, against which the seal is provided, lies in a range between 1 and 4 bar. In the English channel tunnel, this pressure lies in the range of 10 bar. Other tunnels are contemplated and planned in which the pressure, against which sealing should be provided, are substantially higher, e.g., up to 30 bar. Furthermore, reliable sealing should be insured even at a large gap width between the tunnel segments. Also, a gap can be formed as a result of deformation of an initially circular tunnel tube as a result of ovalization.
DE 35 26 063 A1 discloses a sealing profile with two rows of channels offset relative to each other. This sealing profile is incapable to withstand a high water pressure. The sealing profile, which is disclosed in DE-37 20 919 A1 is relatively flat and is not able to seal large gaps at high water pressures. The sealing profile, which is disclosed in DE-40 26 076 A1, becomes displaced upon application of a side water pressure, whereby the intended sealing effect of the expanded legs is cancelled. DE-41 03 089 A1 discloses a sealing profile with two, arranged one above the other, rows of channels, forming continuous vertical and sloping webs. Upon compression, without a sidewise offset of the opposite receiving grooves, this profile becomes deformed, causing pivoting and sidewise displacement of the tunnel segments relative to each other. CH-679 510 discloses a sealing profile with a single row of channels and which, because of its relative flatness, does not provide an adequate sealing against high water pressure at large gap widths. Common for all of the above-discussed sealing profiles is a loss of a sealing effect upon formation of subsequent gaps between the sealed segments even if these gaps are in a mm range. This is because the inner restoring force during expansion is noticeably smaller than during loading as a result of the hysteresis behavior of the elastomeric compression profile.
DE-196 03 188 A1 discloses a sealing profile provided, in its rear region, with an indentation in which a strip-shaped insert is received which is formed of a water-swellable material. Upon penetration of water, the volume of the material increases, providing additional sealing stresses.
Generally, it is known to use seals formed of water-swellable material in building construction, underground works, and other civil engineering works, in particular for sealing joints and for compensation of dimensional changes of the components. Such water-swellable materials are disclosed, e.g., among others, in WO 99/35208, the references cited therein, EP-0692 584 B1 and the references cited therein.
Also known are co-extruded sealing profiles having, in their rear region, a co-extruded water-swellable layer. These seals have a single row channel arrangement. One of such seals is disclosed in CH-679 510 A5.
Even these conventional sealing profiles, which include water-swellable material, are not capable to withstand high water pressures. Besides, e.g., the sealing profile of DE 196 03 188 A1, which includes a water-swellable insert, proved to be very expensive.
Accordingly, an object of the present invention is to provide an elastomeric strand-shaped sealing profile capable to withstand very high water pressures.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a sealing profile including at least one continuous transverse beam located in a region between the base surface and the rear side surface and projecting beyond a base body at the opposite lateral side surfaces, with projecting portions forming two projecting cantilever arms for engaging respective adjacent side surfaces of the receiving groove of the tunnel segment, two sealing lips provided on the base body on respective lateral side surfaces adjacent to regions of corners between the base surface and the respective lateral side surfaces, extending sidewise of the based body and continuously extending in a longitudinal direction of the sealing profile, and formed of a water-swellable material, and two webs extending from corners formed by the rear side surface and respective lateral side surfaces and toward each other, and forming, together with a rear side surface-forming web, a triangular structure, and a further web extending from a tip of the triangular structure and toward the base surface, the two webs and the further web forming together a Y-shaped structure.
The continuous transverse beam with the sidewise projecting, cantilever arms insures that upon a sidewise action of the water pressure, the sealing profile is supported against opposite side surfaces of the receiving groove of the tunnel segment and, therefore, is displaced sidewise by a very limited amount. Preferably, the cantilever arms are provided on a substantially trapezoidal body. With such reversed, with respect to the receiving groove, trapezoidal body, the sealing profile can be so formed that it can be completely inserted into the receiving groove, with the restoring forces remaining within acceptable limits. The maximum value of the restoring force should not be very high in order, e.g., not to chip off the receiving groove rims. The entire cross-sectional surface of the inventive sealing profile can be, e.g., in the range of 90% (xc2x15%) of the cross-sectional surface of the receiving groove.
The expression xe2x80x9csubstantially trapezoidalxe2x80x9d also refers to a body, having in cross-sectional view, lateral side surfaces inclined at different angles, e.g., above and below the sidewise projecting cantilever arms.
The water-side sealing lips, which are provided in corner regions between the base surface and respective lateral side surfaces, upon increase of the water pressure, are pressed against the side surfaces of the receiving groove, providing for an automatic sealing. Upon penetration of water, the sealing pressure is increased due to swelling of the sealing lip material, with increase of the volume of the sealing lips. The sealing lips would be further pressed against the side surfaces of the receiving groove, on one hand, and against the lateral side surfaces of the sealing profile, on the other hand, providing for an increased sealing effect. Preferably, the sealing lips are formed of a softer material than the base body, which provides for good adaptation of the sealing lips to the unevenness of a concrete surface.
The Y-shaped structure according to the present invention insures that the restoring forces are concentrated in the center of the receiving groove. According to a preferred embodiment of the present invention, at least two rows of channels are, distributed over the width of the sealing profile, with one row being provided in a region above the transverse beam and one row being provided below the transverse beam.
Advantageously, the base surface is formed as a closed bottom surface, without slots extending therefrom in the interior of the base body. Such a bottom surface insures a reliable mounting of the sealing profile in the groove, which contributes to the sealing stability.
According to a further preferred embodiment of the invention, a co-extruded insert formed of a water-swellable material is provided in the rear surface of the sealing profile. Upon penetration of water, in particular, as a result of a reduction of the compression sealing, the volume of the insert increases, providing for additional pressure action, whereby the loss of the compression force is compensated or even overcompensated.